I installed Snow Leopard about a week ago on my MacBook Pro (purchased in early 2006). Since then I randomly get a blue screen and all the open applications shut down. I then have to re-open them. It is very annoying! I can't see a pattern but I mostly use Microsoft Office for Mac and it occurs when I am in the middle of a word or excel document. I have found no reference online to this sort of problem. I have not installed any other new software or hardware during this time. Any suggestions?